Infant environmental transition system and method

ABSTRACT

An infant environmental transition system and method provides an infant with a controlled, healthy transistion from an intrauterine environment to the extrauterine environment, and includes a housing within which the infant is supported by a soft, form-fitting bed. Environmental conditions provided within the housing include simulated motions, sounds and tactile sensations resembling the intrauterine environment. A suspension and drive system controls the degree of movement imparted to the housing and to an infant supported therein. The resulting motion closely approximates the motion experienced by the fetus while the mother is walking. The sound profile simulates intrauterine cardiovascular and gastrointestinal sounds. The system simulates day and night variations in motions and sounds, integrates changes to the environment over time toward the natural extrauterine environment, and may respond to infant activity or other inputs at various intervals.

This is a divisional of copending application(s) Ser. No. 07/415,064filed on Sep. 29, 1989 now U.S. Pat. No. 5,037,375.

BACKGROUND OF THE INVENTION

Animals have the ability to adapt to many and varied environmentalconditions. The limit of adaptation depends mainly on the animal'sabsolute physiological limitations and the rate of environmental changeor adaptive pressure to which it is subjected.

Perhaps the most difficult transition a mammal is required to make inits lifetime is the change from the intrauterine environment to theextrauterine environment at birth. Every parameter of the infant'senvironment changes abruptly. Dramatic shifts in temperature, tactilesensation, audio stimuli, motion and light are exacerbated by conditionsin the hospital delivery room where most women in modern societies givebirth. Even the environment in a loving home is alarmingly unfamiliar,and many infants exhibit prolonged crying and sleeplessness which may berelated to transitional stress. It is believed that these abrupt changesin the environment tend to intensify the infant's intrauterine toextrauterine transition and may inflict harm which affects the person'semotional and physical response to adaptive or environmental changethroughout the remainder of his or her life. Therefore a gradual andeffective transition of the infant from the intrauterine environment tothe extrauterine environment may have substantial long-term as well asshort-term benefits.

An effective transition system would duplicate as closely asconveniently possible the intrauterine conditions perceived by theinfant just prior to birth. It would also provide means for graduallyaltering environmental stimuli over time until they reflected thenatural extrauterine environment.

The environmental stimuli vary in complexity and ease of simulation orcontrol. Light and temperatures are relatively easy to simulate andvary. The sound parameter, while complex in nature, may be generated andcontrolled by standard means. The motion parameter, however, is quitedistinctive. FIG. 1 shows the characteristic pelvic displacementpatterns of pregnant women while walking. Duplicating the linear androtational components of these motions is difficult and requires asophisticated suspension and motion control and drive system.

U.S. Pat. No. 4,079,728 discloses a programmable environmentaltransition system with means to provide and control two or more of theabove-mentioned environmental stimuli and to modify them over time frominitial values closely approximating what the fetus perceives in theuterus just prior to birth to final values typical of the extrauterineenvironment. Rather than duplicate any particular motion pattern, thesystem imparts a general rocking motion to the infant, who is suspendedtherein on a net-like sling.

SUMMARY OF THE INVENTION

The present invention incorporates a motion-oriented environmentincluding a suspension and motion control and drive system which veryclosely replicates the intrauterine motion the fetus experiences as themother is walking. A microprocessor integrates desired changes in motionand other stimuli to gradually transition the infant from the simulatedintrauterine environment to the extrauterine environment, and to providewide-ranging system flexibility.

Previous suspension systems commonly generated relatively simplepatterns of motion. They also exhibited undesirable axial and radialplay which increased over time, suffered excessive wear (causing debrisand requiring lubrication and maintenance), and produced unacceptablelevels of noise. Previous systems also created simple intrauterine soundparameters that were variable in volume and operating on-time.

The present system overcomes these significant deficiencies and producesa complex, more natural motion which is completely quiet, smooth andcontinuous, with minimal or no friction, high safety and reliability,and low maintenance. In addition, the present invention automaticallyvaries environmental parameters to simulate normal changes in dailymaternal activity including varying the operating on-time and volume andrate of sound impulses similar to such parameters as would be found inthe biological environment, thus providing the infant with an even morefamiliar and comforting environment. A baseline cyclic rhythm pattern isestablished for day and another similar pattern is established fornight. In addition the impulse frequency (heart rate sounds attenuatedthrough the hydraulic cardiovascular and placental circulation system)vary with the state of movement of the cradle (as would in theintrauterine environment of the mother). Thus, as the complex rockingmotion accelerates slowly, the sound impulse rate also increases in apattern which tracks the random motion pattern through acceleration anddeceleration. When the cradle system is not in motion the soundfrequency reverts slowly back to its baseline (day or night) cyclicrhythm pattern. This sound production system thus closely follows livingbiological patterns that are familiar to the infant. A solar sensor (ormanual switch), working in conjunction with electronic circuitry,reduces the speed of the motion at night, to simulate the mothersleeping, and may also be used to vary the intensity of theenvironmental sounds. Finally, the system integrates the above aspectsof sound, motion, and day/night variation and reduces such stimuli overtime from initial simulation of intrauterine conditions toward naturalextrauterine conditions.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the characteristic pelvic motion patterns ofpregnant women while walking, which patterns are emulated by the motionparameters of the present invention;

FIG. 2 is a side elevational view of the simulator according to oneembodiment of the present invention;

FIG. 3 is an end view of the simulator of FIG. 2;

FIG. 4 is a top cutaway view of the simulator of FIG. 2;

FIG. 5 is a side elevational view of the simulator according to anotherembodiment of the present invention;

FIG. 6 is an end view of the simulator of FIG. 5;

FIG. 7 is a top cutaway view of the simulator of FIG. 5;

FIG. 8 is a cross-sectional end view of still another embodiment of thepresent invention, including wide flexures and flat membrane safetyfeatures;

FIG. 9 is a cross-sectional end view of still another embodiment of thepresent invention, including wide flexures and curved membrane safetyfeatures;

FIGS. 10 (a)-(m) form a flow chart of the electronic control system ofthe present invention;

FIGS. 11 (a) and (b) are graphs which shows changes in sound and motionas a function of infant age during day operation of an embodiment of thepresent invention;

FIG. 11 (b) is a graph which shows changes in sound and motion as afunction of infant age during night operation of an embodiment of thepresent invention;

FIGS. 12 (a)-(c) are graphs which show characteristic 24-hour patternsof sound and motion for three infant age settings in accordance with anembodiment of the present invention; and

FIG. 13 is a block schematic diagram of and embodiment of the electroniccontroller of the present invention.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

Referring now to the drawings and initially to FIGS. 2, 3, 4, 5, 6 and7, there is illustrated an environmental transition system includingsuspension and motion control and drive systems, and including astimulus integration and modulation system, according to the presentinvention. The system provides for a gradual, controlled transition forthe infant by initially simulating its intrauterine environment andgradually transitioning to the extrauterine or everyday environment,thereby reducing adaptive shock and permitting healthy, gradualadaptation. This transition is accomplished by the present system whichinitially reproduces environmental parameters sensed by the infant justprior to birth. In Particular, the system provides and transmits to theinfant, via the suspension and motion control and drive systems, amotion which very closely approximates the motion which a fetusexperiences as the mother is walking. The system is controlled to varyenvironmental parameters in a day-night cycle and to reduce stimuli overtime until the infant is exposed to parameters which approximate theeveryday environment.

The system includes a cradle 1 on a moving platform 30 which issupported for motion along several axes by the suspension systemincluding lower flexure supports 11 and upper flexure supports 3. Thecradle 1 includes a soft, form-fitting mattress 33 on which the infantrests, and includes bolsters 31 with bolster straps 32 to simulate theconfining intrauterine tactile environment.

The system further includes a sound transducer 2 disposed in the cradle1 beneath the level of the infant positioned therein on mattress 33. Thesound transducer 2 may include one or more signal sources connectedthereto such as a phonograph, tape player, electronic signal generator,or similar controllable sound generating device. The sound profilegenerated thereby may comprise a variety of different simulated soundsor actual recordings of the noises present in the near-term pregnantuterus. It may also comprise other sounds such as music or house soundswhich may be generated electronically, recorded on tape, or played froma transmitter and reproduced via a receiver as a signal source in thecradle 1. The sounds are reproduced from the transducer or speaker 2,which is suitably mounted below the mattress 33. The sound directed tothe infant, like other environmental factors, may be gradually changedover a period of a few months from intrauterine sounds to sounds typicalof the outside world.

The cradle 1 is supported by a suspension system which includes fourthin rectangular lower flexures 11 that are formed of spring steel, orthe like, and that have their lower ends affixed to base 27 via lowermounting brackets 29 and their upper ends affixed to the moving platform30 via upper mounting brackets 29. This specific design enables theplatform 30 to undergo essentially linear motion along the longitudinalaxis of the cradle 1 while keeping the moving platform 30 parallel tobase 27 and constrained against lateral movement. As platform 30 movesrelative to base 27, the lower flexures 11 bend as shown by broken lines39.

The platform 30 supports and carries the cradle 1 via the upper flexures3 and associated parts as described below. The upper flexures 3 areformed of thin spring steel, or the like, and are affixed at the centerof the moving platform 30 by the clamp plates 34. The ends of the upperflexures 3 are affixed to the bottom of the cradle 1 by the upper clampplates 35. The cradle 1 is supported by the two cradle pivots 23 whichare affixed to the bottom of cradle 1. As shown in FIGS. 3 and 6, theseupper flexures 3 and cradle pivots 23 enable the cradle 1 to rotateabout the bottom of the cradle pivots 23 while the upper flexures 3 bendas necessary to restrain the cradle 1 against lateral and longitudinalmotion on the platform 30. The specific system design and geometry issuch that the weight of the moving mass counteracts almost all of theforce required to deflect the lower flexures 11. Therefore, the actualforce required to move the mass, which includes cradle and infant, isvery low. This reduces motor requirements and manufacturing costs andincreases the smoothness of the resulting motion.

The characteristic motion of cradle 1, which is comprised of linear androtational components as shown in FIG. 1, may be generated in accordancewith an embodiment described below.

With reference to FIGS. 2, 3 and 4, the motion control and drive systemfor one embodiment of the present invention drives both the linear andangular motions, as shown by the arrows in FIGS. 2 and 3, by means of alow-voltage, alternating-current motor 12 that is controlled by theelectronic circuitry in module 28. As a result of the use of low-voltageAC motor 12, no high voltage is required anywhere in this embodiment,for enhanced product safety. Also, the commutator and brushes of D.C.motors are eliminated with concomitant reductions in the possibilitiesof electrocution, fire or explosion.

Referring now to the linear motion components, motor 12 drive motorpulley 13, which drives primary belt 14, which drives primary drivenpulley 15. This primary speed reduction scheme provides the desiredoscillation speed of the linear motion of cradle 1. The present designincorporates a 300 RPM motor for a daytime cradle speed of about 30linear cycles per minute. The magnitude or frequency of drive signalapplied to the motor 12 may be altered to provide the desired cradlespeed.

Referring again to FIG. 2, linear drive pivot 19, which is on drivenpulley 15, is connected to linear drive link 20, which is connected tolinear drive pin 25, which is affixed to moving platform 30. As shown inFIG. 2, rotation of linear drive pivot 19 about the center of pulley 15drives cradle 1 in linear oscillations along the longitudinal axis ofthe cradle 1. The longitudinal displacement of cradle 1 may be alteredby positioning the drive pivot 19 at different radii on the drivenpulley 15.

Referring now to the rotational motion components, as shown in FIGS. 2and 4, secondary drive pulley 16 drives secondary belt 17, which drivessecondary driven pulley 18, which is connected to shaft 36, which isconnected to drive disk 37. Rotational drive pivot 21 is attached todrive disk 37, which is connected to rotation drive link 22, which isconnected to cradle drive pin 24, which is affixed to the bottom ofcradle 1. Drive bracket 26 supports and provides the pivots for pulley15, pulley 18, shaft 36 and drive disk 37. Belts 14 and 17 are used toprovide both primary and secondary reductions without significant noise.The degrees of rotation of the cradle 1 relative to platform 30 may bealtered by positioning the drive pivot 21 at different radii on drivedisk 37.

The ratio between pulley 16 and pulley 18 may be tailored to provide thedesired relationship between the linear and rotational motions ofcradle 1. The present design utilizes a 2:1 ratio which provides amaximum or daytime cradle rotational motion of about 15 oscillations perminute but, of course, other suitable values may also be used. Thecombined motion control and drive system of this embodiment produces alinear motion of approximately 1.5 inches and rotational motion ofapproximately 9.5 degrees. This motion very closely replicates theintrauterine motions experienced by the fetus while the mother iswalking, as illustrated in FIG. 1 and as translated 90 degrees from themost common "head down" intrauterine position of the fetus to theposition of the infant laying in the cradle 1.

With reference to FIGS. 5, 6 and 7, the motion control and drive systemin another embodiment of the present invention provides the linear androtational motions using separate linear activators or motors 41-44 and45.

The linear motion motor 41-44 consists of a moving coil motor with themoving electromagnet 43 attached to bracket 44 which is attached tomoving platform 30. Motor magnet 42 is attached to bracket 41 which issolidly attached to base 27. Magnet 42 may be an electromagnet, however,the present design utilizes a permanent magnet. Magnet 42 is polarizedas shown, with bracket 41 having a cylindrical center portion whichprovides the circular return path for the magnetic flux. Electromagnet43 is energized and controlled by electronic circuitry in module 28.When electromagnet 43 is energized, the resulting magnetic field causesmoving platform 30 to move to the right or left, depending upon thedirection of the current flow in the coil, as a result of the magneticfield either attracting or repelling the magnetic field of magnet 42.Motion sensor 48 is provided to detect the motion. Motion sensor 48 maybe a simple single stage sensor or a multi-stage device to sense motion,direction of motion, velocity, etc. Such motion sensor 48 may be one ofmany types of devices such as a simple mechanical switch, optical ormagnetic sensor, linear variable differential transformer, encoder, andthe like, for connection to the electronic circuitry in module 28 to setmotion limits, provide conventional feedback control, or the like.

Control of electromagnet 43 by the electronics module 28, in conjunctionwith motion sensor 48, allows simple or sophisticated linear motioncontrol of the cradle 1. Cradle 1 motion may be increased or otherwisemodified by controlling the current, voltage, duration of pulses or thelike, applied to electromagnet 43 in either an "open-" or "closed-loop"type of operation. Also, different phased relationships and differentrelative speeds of translational and rotational motions of the cradle 1may be implemented under control of independent signals supplied to thetwo linear motion motors from the electronic circuitry in module 28.

The rotational motion of cradle 1 is driven by rotation motion motor 45which is connected to cradle 1 by rotation drive pin 47 through rotationdrive link 46. Motor 45 may be similar to motor 41-44 and works inconjunction with a rotational motion sensor similar to motion sensor 48(described above), which is not shown. Motor 45 may be driven in eitheran "open-" or "closed-loop" mode to provide a motion control system.

Motor 41-44 and motor 45 may be controlled completely independently ofeach other, to provide numerous combinations of linear and rotationalmotions of cradle 1. As a result, in addition to replicating the motionthe fetus experiences within the uterus while the mother walks, thesystem can also simulate and transition between many other types ofmotion the fetus perceives during pregnancy. For example, the system cansimulate motion perceived while the mother sleeps, and can then varymotion amplitudes and phase relationships of linear and rotationalmotions to more closely approximate the motion perceived while themother is walking. The controlled transitions are silent and smooth,such as by `ramping` up or down between operating conditions overseveral minutes, so as not to stress or awaken the infant.

FIG. 8 shows an alternate embodiment of the suspension system of thepresent invention. In this embodiment, two wide flexures 58 replace thefour narrow lower flexures 11 shown in FIGS. 2, 3, 5 and 6. Wideflexures 58 are attached to moving platform 52, which supports cradle 1,which rotates substantially about cradle pivot 23. Flat membrane 49 isattached to moving platform 52 by membrane clamping plate 53. The outerend of flat membrane 49 is securely fastened to cradle 1 by membraneretainer 50 which is press fit into membrane groove 51 in cradle 1 toinhibit anyone or anything from being pinched or trapped between movingcradle 1 and moving platform 52. As shown by the phantom lines in FIG.8, the rocking rotational motion of cradle 1 causes flat membrane 49 toexperience only a small amount of stretching, less than 6 percent,because of the specific geometry that places the flat membrane 49 on thehorizontal axis of the cradle 1 pivot point. As a result, flat membrane49 stretch is limited to the difference between the radius swung by theouter end attached to cradle 1 and the radius swung from the innermostend of flat membrane 49. Minimizing stretch of the membrane promoteslong life and makes it possible to use low-cost, flat elastomericmaterials for membrane 49.

FIG. 9 shows an alternate embodiment of the safety mechanism of thepresent invention. This embodiment utilizes a curved membrane 54, whichis attached to cradle 1 by upper clamp plate 56 and to moving platform57 by lower clamp plate 55. The rocking rotation of cradle 1 causescurved membrane 54 to be opened and closed. Resultant stresses aredistributed over the long length of curved membrane 54, to promote longlife of the membrane. The design of curved membrane 54 inhibits anyoneor anything from being pinched or trapped between moving cradle 1 andmoving platform 57 to enhance the safety of the present invention.

The system described above automatically varies the environmentalstimuli of the cradle in a day-night cycle to simulate the mother'sactivities while awake or sleeping. This is accomplished by solar sensor4 working in conjunction with the electronic circuitry in module 28 inthe manner shown in FIGS. 10(a)-(m). The solar sensor 4 detects reducedambient light and switches to the "nighttime" program of motion andsound. Of course, such day or night operating programs may also beimplemented under control of a timer or manual switch. The presentinvention utilizes a night speed of about 50-60% of the day speed, butother ratios may, of course, also be used. Alternatively, individualactuators coupled to the platform 30 and to the cradle 1 may impartindependent motions along the selected axes of motion in daytime andnighttime operations under control of the electronic circuitry in module28. And, the present invention supplies sound volume during nightoperation that is approximately 85-90% of the day volume, but otherratios, of course, may also be used.

The integration of various previously-described aspects of motion andsound generation, day and night variations, and infant age-dependentreduction of stimuli over time, from initial intrauterine values tonatural extrauterine values, is accomplished under control of theelectronic circuitry in module 28, as shown in FIGS. 10(a)-(m) and 12.In one embodiment, a microprocessor may receive inputs from thestop/reset switch 6, start switch 7, age-control slide potentiometer 9,solar sensor 4, and motion sensor such as a switch comprising aphotodiode/photosensor pair (not shown). The microprocessor generatesoutputs which control sound generation through speaker or transducer 2,and which control the speeds of motor 12 or motors 41-44 and 45(depending on the embodiment), the status of indicator lamp 5, and thefunction of a timer.

Considering the electronics control scheme in greater detail, and withreference first to FIG. 10(a), the program begins with Reset uponpower-up or motion time out. Also, if the stop/reset switch 6 ispressed, the program will go to Reset once the sound and motor are off.A timer, when it times out, causes the cycle of operation to beginagain. The controlling program initializes the microprocessor and itsinternal RAM to begin operation. The program checks the test switches tosee if a test mode has been selected. If yes, test routine is exercised.If no, the start switch 7 must then be pressed. Once start switch 7 ispressed, the main sequence for normal operation of the cradle isexercised.

Referring now to FIGS. 10(b)-(c), the program senses the age-controlpulse-width from age-control potentiometer 9 and generates a numberbetween 0 and 255 corresponding to the age setting. Then, the sound,motor, and day-night state processors are initialized. Depending on thestate of the cradle, each processor executes one of its four functions.For example, considering the sound-state processor, the sound will beeither off, turning on, on, or turning off, and the processor willexecute the corresponding subroutine, as shown in FIGS. 10(d)-(e).Similarly, the motor will be either off, turning on, on, or turning off,and the appropriate subroutine will be executed, as shown in FIGS.10(f)-(g). For the day-night state processor, the four states are dayoff (which means it is night), day turning on (which means night isbecoming day), day on (which means it is day) or day turning off (whichmeans day is becoming night), as illustrated in FIGS. 10(h)-(i).

The turn on and turn off functions execute the gradual ramping up ordown of the sound level, motor speed, and day-night transitions. Thesound on-off and motor on-off ramping operations are much faster thanthe day-night transitions, which take about five minutes.

While the cradle is in normal operation, the microprocessor continuouslyexecutes the main control program. After executing the appropriate soundstate, motor state, or day-night state, the system updates themotion-detector time-out values every time the motor speed changes, andthen seeks a motion-detector time out. As shown in FIG. 10(c), the maincontrol program also strobes the timer, scans stop/reset switch 6 forindications of a need to shut down and, if necessary, toggles indicatorlamp 5 once every second.

Referring now to FIGS. 10(d)-(e), the present invention executes one offour sound-state subroutines, depending on the state of the sound, asindicated by the dwell. Dwell is the amount of time the sound is on,expressed either as a percent or as a number between 0 and 255, where255 represents 100%, 128 represents 50%, and so on. If dwell equals 0,the sound is off and will never turn on, i.e., the sound-off loopcontinues to execute each time dwell at 0 is detected (for example, atage equals four months). If dwell is greater than 0, the sound is onpart of the time, and the system seeks the appropriate turn-on time.

The turn-on times are set randomly every time the motor is turned on.The first turn-on time is set at Reset/initialization, when the systemfirst executes the main control program. When the first turn-on time isreached, the sound state changes from SNDS-OFF (sounds off) to soundsT-ON (sounds turn on), and new turn off and turn on times are generatedrandomly. As the system executes the sounds T-ON subroutine in the mainloop, the volume of the sound increases by a given increment eachsecond. The system then checks for whether the volume equals the targetvolume, which will differ depending on whether the cradle is operatingin the day or night state. If the volume does not equal the targetvolume, the subroutine executes again. If the volume does equal thetarget volume, then the sound is as loud as targeted, and the soundstate changes to SNDS-ON (sounds on). Of course, target sound volume maybe set, or the sound profile scheme described above may be replaced, bya conventional manual volume control circuit.

In the SNDS-ON state, the system checks for whether the dwell is lessthan the maximum dwell. If the sound equals maximum dwell, the systemremains in the SNDS-ON state and never turns off. If the dwell is lessthan maximum, the sound turns off when the real-time count of minutesequals the sound turn off time which was randomly set, as previouslydescribed. At that point, the sound state changes to sounds T-OFF(sounds turn off), and the sound decreases every second until the volumeequals 0, at which point the system returns to the SNDS-OFF state.

FIGS. 10(f)-(g) show the motor state subroutines. The motor statesubroutines operate independently from the sound state subroutines butare otherwise very similar. In the MOTS-OFF (motor off) state, thesystem determines whether dwell is greater than 0. If no, the motorremains off. If yes, the system checks whether the current real-timecount of minutes is equal to the randomly-preset turn-on time. If no, itsimply returns. If yes, it randomly sets new turn-off and turn-on times,sets the target speed based on whether the day-night state is day ornight, and changes the motor state to MOTS-TON (motor turn on). TheMOTS-TON routine checks whether the present speed equals the targetspeed. If yes, the system changes to the MOTS-ON (motor on) state, whichchecks whether the current time equals the randomly-set MOTS-TOFF (motorturn off) time. If no, the system returns and checks again the next timethrough. If yes, it sets the target speed to the stop speed, which isnot quite off, and waits for the motion detector trip to go off. Whenthat happens, the system changes states to MOTS-TOFF, which then seeksthe motion interrupt in centering before shutting off completely. TheMOTS-TOFF routine seeks speed equal to the target speed setting beforestopping. Once the target speed is reached the first time, the routineseeks the motion interrupt count generated by the real-timecount-interrupt routine.

Because the ramping for motor speed is faster than the ramping for soundvolume, it is easiest to handle motor-speed transitions in the real-timecount-interrupt routine. The motion detection interrupt routine, shownin FIG. 10(m), is very simple. Every time the motion detector trips orswitches, it increments a byte in memory or register. The motor stateprocessor detects that byte in memory as an indication that the motiondetector has been tripped.

Each clock timer overflow results in a clock interrupt and execution ofthe motor-control interrupt routine, as shown in FIG. 10(l). Theoverflow is currently set for about every 50 milliseconds. The interruptincrements bytes in memory. One byte counts the 50 millisecondinterrupts. Once the system accumulates 20 such interrupts, it updatesthe byte called "seconds." Once it accumulates 60 "seconds" itincrements the byte called "minutes"; after accumulating 60 "minutes" itincrements the byte called "hours"; after accumulating 24 "hours" itincrements the byte called "days." The system also includes a bytecalled "10 days" (not presently used). After incrementing the real-timeclock bytes as necessary, the system checks whether it is time tocontrol the motor. If yes, then the system increases or decreases motorspeed, depending on whether the motor state is MOTS-TON or MOTS-TOFF.

FIGS. 10(h)-(i) show the day-night state subroutines. The day-nightstate processor reads the output of solar sensor 4. If the outputindicates light has been detected, it increments a byte called "daycount"; otherwise it decrements day count. A day count reading of 5,000indicates that the solar sensor 4 has detected light 5,000 times moreoften than it has detected no light. Similarly, a day count reading of-5,000 indicates that the solar sensor 4 has detected no light 5,000times more often than it has detected light.

State DAYS-OFF is equivalent to nighttime. Once the day count reaches5,000, which means light is detected much more frequently than no light,the system increments the motor dwell to the day dwell value. It alsochanges the state to DAYS-TON (days turn on), which increments thevolume of the sound which includes heart sounds (the beat rate of whichis also increased), and increments motor speeds every minute until theyreach the preset daytime values. At that point, the system changesstates to DAYS-ON (days on), where it continues to read the output fromsolar sensor 4 until it indicates it has seen no light 5,000 times moreoften than it has seen light. When that occurs, the system sets themotor dwell to the night dwell value and changes the state to DAYS-TOFF(days turn off). While in the DAYS-TOFF state, the system decreases thesound volume, heart-beat rate and motor speed until they reach theirpreset night values, in approximately 5 minutes. Finally, the systemchanges back to the DAYS-OFF (night) state. It should be noted that thesolar sensor 4 is checked repeatedly to ensure against false "daytime"detection, for example, on sensing the transient condition of a lampturned on briefly in the proximity of the cradle.

FIG. 10(j) shows the SLOW-STOP and CHECK-MOTOR subroutines. The systementers the SLOW-STOP subroutine from the main control program whenstop/reset switch 6 is pressed. First, the subroutine increases themotor ramp rate so the motor turns off faster (though, not instantly)than it normally would. Second, it sets the motor target speed to thestopping speed used to check for centering of the cradle. Once the motorand sound are both off, the system jumps back to location 0, which isthe reset position in FIG. 10(a). If either the motor or sound or bothare still on, the system uses the MOT-TOFF and SNDS-TOFF routines todecrease the motor speed and sound volume and to center the cradle.

The check motor subroutine, which is ignored in test mode, is used totime out in the case where the no motion detector is seen. In normalcradle operation, where the motor speed is greater than 0 (i.e., themotor is actually on), the system checks to see if the motion end (thebyte that is incremented when the motion detector trip interrupt isexecuted) is greater than 0. If yes, this indicates a trip and thesystem executes the TO-CHECK (time out check) routine to set a timevalue to indicate when in the future the system will time out. If thecurrent seconds elapsed value from the real-time clock interrupt equalsthe time-out time, the system resets i.e., goes back to the resetlocation in FIG. 10(a), thus indicating that the system has timed outand stopped. If the current seconds elapsed value from the real-timeclock interrupt does not equal the time-out time, the system returns andthe routine will be ignored.

FIG. 10(k) shows the sound generation interrupt. The interrupt ratedetermines the heart rate. The sound interrupt reads the next data valuefrom the sound data table and writes it to the sound DAC after scalingit to the current sound volume setting. When it reaches the end of thetable, the system resets its pointer and restarts at the beginning.

The motion generation means, under the control of thepreviously-described electronic circuitry in module 28, operates withinthe following general parameters. The cradle motor 12, or cradle motors41-44 and 45, depending on the embodiment, will be turned on and offrandomly while the cradle 1 is in operation. The minimum on-time isabout 5 minutes and maximum on-time is about 45 minutes. The gradualtransition between on and off takes about 30 seconds. (The motor on-timeis counted from when the motor first begins to turn on until it iscompletely off again.) The motor dwell declines linearly from about 50%at minimum age to 0% at maximum age. Of course, other time intervals anddwell ratios may also be used.

Similarly, the sound generation means operates within following generalparameters. The sound will be turned on and off randomly while thecradle 1 is in operation. The minimum on-time is about 5 minutes and themaximum on-time is about 45 minutes. The gradual transition between onand off takes about 30 seconds. (The sound on-time will be counted fromwhen the sound first begins to turn on until it is completely offagain.) The sound dwell declines linearly from about 100% at minimum ageto 0% at maximum age. The simulated heart beat rate is about 80 beatsper minute for daytime operation and about 62 beats per minute fornighttime operation to simulate typical active and at-rest heart rates.Of course, other rates may also be used, and the transition from day tonight rates takes about 15 minutes.

The characteristic interrelationships among the parameters aregraphically displayed in FIGS. 11 and 12.

FIGS. 11(a) and (b) show the gradual change in the duration andfrequency of sound and motion as a function of infant age (from 0-4months) for the day and night operational modes (FIGS. 11(a) and (b),respectively) of the present invention. In general, the motion is fasterand the heartbeat sound is faster and louder in the day mode than in thenight mode. As the infant ages, the amount of time the motion and soundparameters are "ON" decreases gradually, but the rates of the motion andheartbeat sounds remain the same. At the end of the transition period,shown here as age 4 months, cradle motion and sounds cease completely.

FIGS. 12(a)-(c) show characteristic on-off and intensity cycles for atypical 24 hour period at infant age settings of newborn, 2 months and 3months. The motion and sound both start when start switch 7 is pressed.Subsequently, however, the motion and sound on-off times may berandomized independently of each other (as illustrated in the leftportion of FIG. 12 (a), or may track at least to the extent of the rampup and down between a base level (day or night) and an elevated levelrepresentative of increased heart rate associated with movements (asillustrated in the remaining portions of FIGS. 12(a), (b) and (c)). Theparticular patterns shown in FIGS. 12(a)-(c), therefore, arerepresentative only of typical random patterns and the decrease in therandom activity with the age of the infant.

In addition to the patterns shown in FIGS. 11(a) and (b) and 12(a)-(c),and the general parameters described above, further alternatives existfor control of sound and motion in the present invention. These include(1) gradually reducing sound amplitude in a linear or nonlinear fashionover the 4 month period rather than full on-off cycles; (2) graduallyreducing the rate (cycles/minute) and/or amplitude (length of stroke) ofmotion, rather than on-off cycles; (3) varying the "normal" sound rate(80 beats/minute-day, 62 beats/minute-night) and "normal" motion rate(30 cycles/minute-day, 15 cycles/minutes- night) as a function of themother's baseline heart rate; (4) varying the 4 month use period; and(5) varying sound and motion rates as a function of specific infantactivities (e.g. pushing a lever).

Referring now to the block schematic diagram of FIG. 13, there is shownthe circuitry in one embodiment of the electronics module 28 includingthe microprocessor 61, the memory address latch 62, the EPROM memory 63,and the crystal clock 71 which control program execution. The primaryoutputs are sound through digital-to-analog converter 64 and amplifier65 to speaker 66, and the motion of motor 12 that is powered byamplifier 68 and digital-to-analog converter 67. Of course, two suchmotor control circuits are included for separate motors or linearactuators such as actuators 41-44 and 45. The microprocessor 61 controlsthese outputs in conventional manner using 8-bit control words appliedto the D/A converters 64, 67. The output from D/A converter 64 issupplied to audio amplifier 65 which drives the speaker 66. The motor 12(or 41-44 and 45) is controlled through D/A converter 67 which receivesan 8-bit control word from microprocessor 61 and which supplies outputto power amplifier 68 that drives the motor.

The particular sound and sound patterns delivered by the speaker 66 areattributable to the sounds that are digitized and stored in EPROM memory63, which sounds may be previously-recorded actual intrauterine sounds.The particular amounts of time that the sounds and the motor motions arein the on-states, and the amplitudes, and the durations controlled byalgorithms stored in the memory 63.

In operation of the system, the algorithms, for controlling the amountof time for the sounds and the motor(s) to be in the on-states can bechanged by an input provided through the age timer 74 and its associatedslide potentiometer 9, 77. The slide potentiometer 9, 77 is locatedconveniently in the front control panel 8 of the cradle and iscontrolled by the user. Other inputs which the user may control includethe start/stop switch 75 and day/night switch 76. Start/stop switch 75controls the starting and the stopping of the system, and the day/nightswitch 76 determines whether the system should be operating in the daymode or the night mode. Each of the switches 75, 76 includes anassociated indicator light 78, 79. Thus, the light 78 associated withthe start/stop switch 75 indicates whether the system is running or isin a stopping mode. When the system is running or is in the stoppingmode, the indicator 78 flashes slowly, for example, at a one-secondrate. When the system has stopped (and is therefore ready to start), thelight 78 is continuously on. Indicator light 79 indicates operation ofthe system in the day mode when the light is off, and in the night modewhen the light is on. In addition to the user controls and the outputsthus described, the system also includes a photo detector assembly 72including optical transmitter and receiver which are positioned tomonitor the cradle motion, for example, as represented by the rotationof one of the secondary gears driven by motor 12. Signals thus producedby the photo detector assembly 12 are continually supplied to themicroprocessor 61 to generate an interrupt or other control signal inthe microprocessor 61. If such control signal ceases to occur, a delayinterval will time-out in the microprocessor 61 after which themicroprocessor 61 will shut down the entire system by turning off powerto the motor and turning off the sound as a safety response, forexample, to the motor 12 stalling or to the belt driving one of thesecondary gears breaking. An additional safety response is provided bywatchdog timer 73 which functions to constantly monitor the properoperation of the program execution by the microprocessor 61. Thiswatchdog timer 73 automatically turns off the microprocessor 61 if thewatchdog timer 73 is not reset within a 2-second interval that isincluded in normal program-controlled operation of the microprocessor61. Thus, in normal operation, the watchdog timer 73 will always bereset within the 2-second interval. However, if a power failure orlow-voltage condition occurs that might cause the microprocessor 61 todeviate from normal program execution, then the watchdog timer 73automatically stops the microprocessor 61 at the expiration of the2-second interval. Various test switches 70 are provided as inputs forcontrolling the operation of the microprocessor 61 in different testmodes to facilitate debugging during manufacturing and system testingdoing field service.

It should be apparent from the foregoing that the preferred embodimentsof the invention provide an apparatus and method which can initiallysimulate the environmental parameters of the near-term gravid uterus,particularly motion and sound, and can transition the infant from thesimulated intrauterine environment to an extrauterine environment. Otherembodiments of the present invention include a platform capable ofimparting the above-described two-axis motion to an incubator for aninfant, or other housing for an individual, that is supported on suchplatform. Also, the sound motion and sound profiles described above maybe manually-controlled or continuous as desired for a particular infantor individual.

What is claimed is:
 1. An environmental control system comprising:ahousing, having a longitudinal axis, mounted for translational motionalong said axis and for rotational motion substantially about said axis;and motive means coupled to said housing for imparting saidtranslational and rotational motions thereto relative to said axis toapproximate the motion experienced by a fetus while its mother iswalking.
 2. The control system of claim 1 comprising:sensor meansdisposed to respond to ambient light level and coupled to the motivemeans for altering a selected parameter of the motions imparted therebyto the housing.
 3. The control system of claim 1 comprising:sound meansincluding a transducer disposed in said housing at a location beneaththe level of an individual supported therein for generating ak soundprofile approximating at least one of intrauterine cardiovascular,digestive and respiratory sounds.
 4. The control system of claim 1comprising:sound means including a transducer disposed in said housingfor generating a first sound profile approximating at least one ofintrauterine cardiovascular, digestive and respiratory sounds, and asecond sound profile substantially approximating sounds in anextrauterine environment, and disposed to alter the sound profile in thehousing over time initially from the first sound profile toward thesecond sound profile.
 5. An environmental control system comprising:ahousing and a base and an intermediate support; mounting means includinglower support means mounted between the base and the intermediatesupport, and including upper support means mounted between theintermediate support and said housing for supporting the movementthereof along at least two axes, at least one of said upper and lowersupport means including flexure members attached to the intermediatesupport for supporting the housing during movement thereof in at leastone of translational and rotational motions about said axes; and motivemeans coupled to said housing for imparting said movements theretorelative to said axes.
 6. The control system of claim 5 wherein saidlower support members includes flexure members attached to the base andto the intermediate support for supporting the movement thereof along alongitudinal axis relative to the base, and wherein said upper supportmeans includes flexure members attached to the intermediate support andto the housing for supporting the rotational movement thereof about anaxis substantially parallel to the longitudinal axis.
 7. The controlsystem of claim 6 wherein the flexure members of said lower supportmembers includes resilient substantially planar members attached to thebase and to the intermediate support, and wherein the flexure members ofthe upper support members includes resilient substantially arcuateflexure members attached to the intermediate support and housing andincluding pivoting means disposed between the housing and theintermediate support to provide elevational stability thereto relativeto the intermediate support.
 8. The control system of claim 5 whereinsaid motive means is coupled to the intermediate support for impartinglongitudinal motion thereto relative to the base and for impartingrotational motion to the housing about an axis substantially parallel tothe longitudinal motion of the intermediate support.
 9. The controlsystem of claim 8 wherein said motive means includes a first motorcoupled to impart longitudinal motion to the intermediate support, and asecond motor coupled to impart rotational motion to the housing.
 10. Thecontrol system of claim 9 wherein said first and second motors includelinear actuators.
 11. The control system of claim 5 comprising:anelastic membrane attached to the housing and to one of the intermediatesupport and base for covering relatively moving perimeters thereof. 12.The control system of claim 5 wherein said motive means includes a motorcoupled to impart both longitudinal motion to the intermediate supportnd rotational motion to the housing.